Design of "Crack-free" Concrete Materials with Robust Self-healing Functionality

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This grant provides funding for the development of virtually "crack-free" concrete materials capable of elevating material durability and extending structural service life by self-sealing porous cracks and autogenously regenerating mechanical performance after damage. This will be accomplished through experimental studies examining the physical and chemical material requirements and environmental exposures that best promote self-healing. Material design based on micromechanics of crack initiation and propagation to control crack width to below 60 m under typical structural service conditions will be emphasized. Nano and microscale phenomena of ion transport, crystal formation and growth into self-healed products will be determined. Supporting this work is a set of existing and newly developed experimental tests to evaluate the reliability, quality and repeatability of self-healing. These tests include dynamic modulus measurements, uniaxial tensile test, water permeability test, nano-indentor and XEDS. As a result, the extent of self-healing both in transport as well as in mechanical properties will be determined.If successful, this research will provide a systematic methodology for designing robust concrete material which is virtually "crack-free." This have significant economic, social and environmental impacts on the United States, through enhancement of the durability and reduction of maintenance needs and cost of infrastructures such as bridges and roadways. Apart from durability, self-healing concretes offer higher performance in structural safety and cost-effectiveness by regenerating after damage, becoming a powerful tool for engineers charged to create structures conforming to increasingly higher requirements. The impacts of this research look to promulgate a significant design paradigm shift not only among construction engineers, but the larger engineering design community through methods for development of robust self-healing composites.